Semiconductor devices having resistors

ABSTRACT

A semiconductor device having a resistor and a method of fabricating the same are provided. The semiconductor device includes a semiconductor substrate having a first circuit region and a second circuit region. A lower interlayer insulating layer is provided over the semiconductor substrate. A first hole passing through the lower interlayer insulating layer in the first circuit region and a second hole passing through the lower interlayer insulating layer in the second circuit region are provided. A first semiconductor pattern and a second semiconductor pattern are sequentially stacked in the first hole. A first resistor having the same crystalline structure as the second semiconductor pattern is provided in the second hole.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of and claims priority from U.S.patent application Ser. No. 12/248,470, filed on Oct. 9, 2008, now U.S.Pat. No 7,871,890 which claims priority under 35 USC §119 from KoreanPatent Application No. 10-2007-0102007, filed on Oct. 10, 2007, thedisclosure of which is hereby incorporated herein by reference in itsentirety.

FIELD

The present inventive concept relates to semiconductor devices andmethods of fabricating the same, and more particularly, to semiconductordevices having resistors and methods of fabricating the same.

BACKGROUND

Generally, a semiconductor memory device includes a cell array regionconstituted by a plurality of unit cells, and a peripheral regiondisposed outside the cell array region to drive and control the unitcells. Several devices such as a transistor, a diode and a resistor areformed in the peripheral region to drive the unit cells.

SUMMARY

According to one aspect of the present inventive concept, asemiconductor device having a resistor includes: a semiconductorsubstrate having a first circuit region and a second circuit region; alower interlayer insulating layer over the semiconductor substrate; afirst hole passing through the lower interlayer insulating layer in thefirst circuit region, and a second hole passing through the lowerinterlayer insulating layer in the second circuit region; a firstsemiconductor pattern and a second semiconductor pattern, which aresequentially stacked in the first hole; and a first resistor provided inthe second hole and having the same crystalline structure as the secondsemiconductor pattern.

In some embodiments, the first and second semiconductor patterns may besingle crystalline semiconductor patterns.

In another embodiment, the first resistor may have a top surfacepositioned at the same level as that of the second semiconductorpattern.

In still another embodiment, a word line may be disposed between thelower interlayer insulating layer and the semiconductor substrate in thefirst circuit region, and have a different conductivity type from thesemiconductor substrate in the first circuit region and a separationlayer may cover a sidewall of the word line. Here, the first hole mayexpose a predetermined region of the word line.

The first semiconductor pattern may have the same conductivity type asthe word line and a lower impurity concentration than the word line, andthe second semiconductor pattern may have a different conductivity typefrom the word line. Alternatively, the first semiconductor pattern mayhave the same conductivity type as the second semiconductor pattern, alower impurity concentration than the second semiconductor pattern, anda different conductivity type from the word line.

In yet another embodiment, a second resistor may be disposed between thelower interlayer insulating layer and the semiconductor substrate in thesecond circuit region, and have a different conductivity type from thesemiconductor substrate in the second circuit region; and a separationlayer may cover a sidewall of the second resistor. Here, the second holemay expose a predetermined region of the second resistor.

Furthermore, a barrier impurity region may be interposed between thefirst resistor and the second resistor.

Meanwhile, the first and second resistors may have differentconductivity types from each other, and the barrier impurity region mayhave the same conductivity type as the first resistor and a lowerimpurity concentration than the first resistor. Alternatively, the firstand second resistors may have different conductivity types from eachother, and the barrier impurity region may have the same conductivitytype as the second resistor and a lower impurity concentration than thesecond resistor. Alternatively, the first and second resistors may havethe same conductivity type, and the barrier impurity region may have adifferent conductivity type from the first and second resistors.

Furthermore, the semiconductor device may further include an upperinterlayer insulating layer disposed over the lower interlayerinsulating layer; a first lower resistor contact plug electricallyconnected with one end of the second resistor and a second lowerresistor contact plug electrically connected with the other end of thesecond resistor, which pass through the upper interlayer insulatinglayer and the lower interlayer insulating layer in the second circuitregion; a first upper resistor contact plug electrically connected withone end of the second resistor and a second upper resistor contact plugelectrically connected with the other end of the second resistor, whichpass through the upper interlayer insulating layer in the second circuitregion; a first lower resistor interconnection covering the first lowerresistor contact plug and a second lower resistor interconnectioncovering the second lower resistor contact plug, which are provided onthe upper interlayer insulating layer in the second circuit region; anda first upper resistor interconnection covering the first upper resistorcontact plug and a second upper resistor interconnection covering thesecond upper resistor contact plug, which are provided on the upperinterlayer insulating layer in the second circuit region. Alternatively,the semiconductor device may further include an upper interlayerinsulating layer disposed over the lower interlayer insulating layer; afirst lower resistor contact plug electrically connected with one end ofthe second resistor and a second lower resistor contact plugelectrically connected with the other end of the second resistor, whichpass through the upper interlayer insulating layer and the lowerinterlayer insulating layer in the second circuit region; a first upperresistor contact plug electrically connected with one end of the secondresistor and a second upper resistor contact plug electrically connectedwith the other end of the second resistor, which pass through the upperinterlayer insulating layer in the second circuit region; a first lowerresistor interconnection covering the first lower resistor contact plugand a first upper resistor interconnection covering the first upperresistor contact plug, which are provided on the upper interlayerinsulating layer in the second circuit region; and a resistor connectingpattern provided on the upper interlayer insulating layer in the secondcircuit region and in contact with the second lower resistor contactplug and the second upper resistor contact plug.

According to another aspect of the present inventive concept, a methodof fabricating a semiconductor device includes: preparing asemiconductor substrate having a first circuit region and a secondcircuit region; forming a lower interlayer insulating layer on thesemiconductor substrate having the first and second circuit regions;patterning the lower interlayer insulating layer to form a first holepassing through the lower interlayer insulating layer in the firstcircuit region and a second hole passing through the lower interlayerinsulating layer in the second circuit region; forming a firstsemiconductor pattern and a second semiconductor pattern, which aresequentially stacked in the first hole; and forming a barrier impurityregion and a first resistor, which are sequentially stacked in thesecond hole.

In some embodiments, the first and second semiconductor patterns, thebarrier impurity region and the first resistor may be formed to have thesame crystalline structure.

In another embodiment, the first and second semiconductor patterns, thebarrier impurity region and the first resistor may be single crystallinesemiconductor patterns.

In still another embodiment, before forming the lower interlayerinsulating layer, the method of fabricating the semiconductor device mayfurther include: forming a separation layer in the semiconductorsubstrate to define a first active region in the first circuit regionand a second active region in the second circuit region; injectingimpurity ions having a different conductivity type from thesemiconductor substrate in the first circuit region into the firstactive region to form a word line; and injecting impurity ions having adifferent conductivity type from the semiconductor substrate in thesecond circuit region into the second active region to form a secondresistor. Here, the separation layer may be formed to cover a sidewallof the word line and a sidewall of the second resistor, the first holemay be formed to expose a predetermined region of the word line, and thesecond hole may be formed to expose a predetermined region of the secondresistor.

Furthermore, the method of fabricating the semiconductor device mayfurther include: forming an upper interlayer insulating layer over thesemiconductor substrate having the first resistor and the secondsemiconductor pattern; forming a first lower resistor contact plugelectrically connected with one end of the second resistor and a secondlower resistor contact plug electrically connected with the other end ofthe second resistor, which pass through the upper and lower interlayerinsulating layers in the second circuit region; forming a first upperresistor contact plug electrically connected with one end of the firstresistor and a second upper resistor contact plug electrically connectedwith the other end of the first resistor, which pass through the upperinterlayer insulating layer in the second circuit region; forming afirst lower resistor interconnection covering the first lower resistorcontact plug and a second lower resistor interconnection covering thesecond lower resistor contact plug, which are formed on the upperinterlayer insulating layer in the second circuit region; and forming afirst upper resistor interconnection covering the first upper resistorcontact plug and a second upper resistor interconnection covering thesecond upper resistor contact plug, which are formed on the upperinterlayer insulating layer in the second circuit region. Alternatively,the method of fabricating the semiconductor device may further include:forming an upper interlayer insulating layer over the semiconductorsubstrate having the first resistor and the second semiconductorpattern; forming a first lower resistor contact plug electricallyconnected with one end of the second resistor and a second lowerresistor contact plug electrically connected with the other end of thesecond resistor, which pass through the upper and lower interlayerinsulating layers in the second circuit region; forming a first upperresistor contact plug electrically connected with one end of the firstresistor and a second upper resistor contact plug electrically connectedwith the other end of the first resistor, which pass through the upperinterlayer insulating layer in the second circuit region; forming afirst lower resistor interconnection covering the first lower resistorcontact plug and a first upper resistor interconnection covering thefirst upper resistor contact plug, which are formed on the upperinterlayer insulating layer in the second circuit region; and forming aresistor connecting pattern in contact with the second lower resistorcontact plug and the second upper resistor contact plug on the upperinterlayer insulating layer in the second circuit region.

In yet another embodiment, forming the first and second semiconductorpatterns, the barrier impurity region and the first resistor mayinclude: forming a cell semiconductor pattern in the first hole, and aperipheral semiconductor pattern in the second hole; doping a lowerregion of the cell semiconductor pattern with impurities having a firstconductivity type or a second conductivity type different from the firstconductivity type using an ion injection technique; doping an upperregion of the cell semiconductor pattern with impurities having thefirst conductivity type using the ion injection technique; doping alower region of the peripheral semiconductor pattern with impuritieshaving the first conductivity type or the second conductivity type usingthe ion injection technique; and doping an upper region of theperipheral semiconductor pattern with impurities having the firstconductivity type or the second conductivity type using the ioninjection technique.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a semiconductor device according to anexemplary embodiment of the present invention;

FIGS. 2A to 2E are cross-sectional views of the semiconductor deviceaccording to the exemplary embodiment of the present invention; and

FIG. 3 is a cross-sectional view of a semiconductor device according toanother exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

The present invention will now be described more fully hereinafter withreference to the accompanying drawings, in which embodiments of theinvention are shown. This invention, however, may be embodied in manydifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. In thedrawings, the thicknesses of layers and regions are exaggerated forclarity. Like numbers refer to like elements throughout.

It will be understood that when an element or layer is referred to asbeing “on”, “connected to” or “coupled to” another element or layer, itcan be directly on, connected or coupled to the other element, or layeror intervening elements or layers may be present. In contrast, when anelement is referred to as being “directly on,” “directly connected to”or “directly coupled to” another element or layer, there are nointervening elements or layers present. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers and/or sections, these elements, components, regions, layersand/or sections should not be limited by these terms. These terms areonly used to distinguish one element, component, region, layer orsection from another region, layer or section. Thus, a first element,component, region, layer or section discussed below could be termed asecond element, component, region, layer or section without departingfrom the teachings of the present invention.

Spatially relative terms, such as “beneath”, “below”, “bottom”, “lower”,“above”, “top”, “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. It will beunderstood that the spatially relative terms are intended to encompassdifferent orientations of the device in use or operation in addition tothe orientation depicted in the figures. For example, if the device inthe figures is turned over, elements described as “below” or “beneath”other elements or features would then be oriented “above” the otherelements or features. Thus, the exemplary term “below” can encompassboth an orientation of above and below. The device may be otherwiseoriented (rotated 90 degrees or at other orientations) and the spatiallyrelative descriptors used herein interpreted accordingly. Also, as usedherein, “lateral” refers to a direction that is substantially orthogonalto a vertical direction.

The terminology used herein is for the purpose of describing particularembodiments only, and is not intended to be limiting of the presentinvention. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof.

Example embodiments of the present invention are described herein withreference to cross-section illustrations that are schematicillustrations of idealized embodiments (and intermediate structures) ofthe invention. As such, variations from the shapes of the illustrationsas a result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments of the present invention shouldnot be construed as limited to the particular shapes of regionsillustrated herein but are to include deviations in shapes that result,for example, from manufacturing. For example, an implanted regionillustrated as a rectangle will, typically, have rounded or curvedfeatures and/or a gradient of implant concentration at its edges ratherthan a binary change from implanted to non-implanted region. Likewise, aburied region formed by implantation may result in some implantation inthe region between the buried region and the surface through which theimplantation takes place. Thus, the regions illustrated in the figuresare schematic in nature and their shapes are not intended to illustratethe actual shape of a region of a device and are not intended to limitthe scope of the present invention.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs.Accordingly, these terms can include equivalent terms that are createdafter such time. It will be further understood that terms, such as thosedefined in commonly used dictionaries, should be interpreted as having ameaning that is consistent with their meaning in the presentspecification and in the context of the relevant art, and will not beinterpreted in an idealized or overly formal sense unless expressly sodefined herein.

FIG. 1 is a plan view of a semiconductor device according to anexemplary embodiment of the present invention, FIGS. 2A to 2E arecross-sectional views taken along line I-I′ of FIG. 1 to explain thesemiconductor device according to the exemplary embodiment of thepresent invention, and FIG. 3 is a cross-sectional view of asemiconductor device according to another exemplary embodiment of thepresent invention. In FIGS. 1, 2A to 2E and 3, “C” denotes a firstcircuit region, and “P” denotes a second circuit region.

First, a semiconductor device according to an exemplary embodiment ofthe present invention will be described with reference to FIGS. 1 and2E.

Referring to FIGS. 1 and 2E, a semiconductor substrate 100 having afirst circuit region C and a second circuit region P is provided. Thefirst circuit region C may be a memory cell array region, and the secondcircuit region P may be a peripheral circuit region. Meanwhile, thefirst circuit region C may be an active circuit region, and the secondcircuit region P may be a passive circuit region. The semiconductorsubstrate 100 may be a single crystalline silicon substrate. Further,the semiconductor substrate 100 may include materials such as siliconcarbide (SiC), silicon germanium (SiGe) and gallium arsenic (GaAs).

A separation layer 105 s may be provided in the semiconductor substrate100 to define a first active region 105 a and a second active region 105b. The first active region 105 a may be defined in the first circuitregion C, and the second active region 105 b may be defined in thesecond circuit region P. A word line 110 a having a differentconductivity type from the semiconductor substrate 100 in the firstcircuit region C may be provided in the first active region 105 a.Further, a lower resistor 110 b having a different conductivity typefrom the semiconductor substrate 100 in the second circuit region P maybe provided in the second active region 105 b. The word line 110 a andthe lower resistor 110 b may have a single crystalline semiconductorstructure.

Bottom surfaces of the word line 110 a and the lower resistor 110 b maybe positioned at a higher level than that of the separation layer 105 s.The separation layer 105 s in the first circuit region C may cover asidewall of the word line 110 a. In the same manner, the separationlayer 105 s in the second circuit region P may cover a sidewall of thelower resistor 110 b. Accordingly, the separation layer 105 s in thefirst circuit region C may electrically insulate the word line 110 afrom another word line adjacent thereto. Similarly, the separation layer105 s in the second circuit region P may electrically insulate the lowerresistor 110 b from another lower resistor adjacent thereto.

A lower interlayer insulating layer 115 may be provided to cover theseparation layer 105 s, the word line 110 a and the lower resistor 105b. A cell diode hole or opening 115 a may be provided to pass throughthe lower interlayer insulating layer 115 in the first circuit region Cand expose a predetermined region of the word line 110 a. A peripheralresistance hole or opening 115 b may be provided to pass through thelower interlayer insulating layer 115 in the second circuit region P andexpose a predetermined region of the lower resistor 110 b.

A first semiconductor pattern 120 a and a second semiconductor pattern125 a may be sequentially stacked in the cell diode hole 115 a. Thefirst and second semiconductor patterns 120 a and 125 a may be singlecrystalline semiconductor patterns. For example, the first and secondsemiconductor patterns 120 a and 125 b may be single crystalline siliconpatterns.

The second semiconductor pattern 125 a and the word line 110 a havedifferent conductivity types from each other, and the firstsemiconductor pattern 120 a and the word line 110 a may have the sameconductivity type as each other. For example, when the semiconductorsubstrate 100 in the first circuit region C is p-type and the word line110 a is n-type, the first semiconductor pattern 120 a may be n-type,and the second semiconductor pattern 125 a may be p-type. Thus, thefirst and second semiconductor patterns 120 a and 125 a sequentiallystacked in the cell diode hole 115 a may constitute a cell diode. Here,the first semiconductor pattern 120 a may have a lower impurityconcentration than the word line 110 a. This is because when a reversebias is applied to the cell diode, leakage current flowing through thecell diode can be minimized. On the other hand, the second semiconductorpattern 125 a and the word line 110 a may have different conductivitytypes from each other, and the first and second semiconductor patterns120 a and the 125 a may have the same conductivity type as each other.For example, when the semiconductor substrate 100 in the first circuitregion C is p-type and the word line 110 a is n-type, the first andsecond semiconductor patterns 120 a and 125 a may be p-type. Thus, theword line 110 a and the first semiconductor pattern 120 a in contactwith the word line 110 a may constitute a cell diode. Here, the firstsemiconductor pattern 120 a may have a lower impurity concentration thanthe second semiconductor pattern 125 a. This is because when a reversebias is applied to the cell diode, leakage current flowing through thecell diode may be minimized.

An upper resistor 125 b may be formed in the peripheral resistance hole115 b. The upper resistor 125 b may have substantially the samecrystalline structure as the second semiconductor pattern 125 a. Forexample, both the upper resistor 125 b and the second semiconductorpattern 125 a may have a single crystalline semiconductor structure. Theupper resistor 125 b may have a top surface positioned at substantiallythe same level as that of the second semiconductor pattern 125 a. Theupper resistor 125 b may be positioned at substantially the same levelas the second semiconductor pattern 125 a. A barrier impurity region 120b may be formed between the upper resistor 125 b and the lower resistor110 b. The barrier impurity region 120 b may be provided in theperipheral resistance hole 115 b, and positioned at substantially thesame level as the first semiconductor pattern 120 a. The barrierimpurity region 120 b and the upper resistor 125 b may be singlecrystalline semiconductor patterns. For example, the barrier impurityregion 120 b and the upper resistor 125 b may be single crystallinesilicon patterns. In the present invention, the upper resistor 125 b maybe represented as a first resistor, and the lower resistor 110 b may berepresented as a second resistor.

In the present embodiment, the upper resistor 125 b and the lowerresistor 110 b may have different conductivity types from each other.The barrier impurity region 120 b may have the same conductivity type asthe lower resistor 110 b, and may have a lower impurity concentrationthan the lower resistor 110 b. For example, when the semiconductorsubstrate 100 in the second circuit region P is p-type, the lowerresistor 110 b may be an n-type semiconductor pattern, the barrierimpurity region 120 b may be an n-type semiconductor pattern with alower impurity concentration than the lower resistor 110 b, and theupper resistor 125 b may be a p-type semiconductor pattern.

In another embodiment, the upper resistor 125 b and the lower resistor110 b may have different conductivity types from each other. Further,the barrier impurity region 120 b may have the same conductivity type asthe upper resistor 125 b, and may have a lower impurity concentrationthan the upper resistor 125 b. For example, when the semiconductorsubstrate 100 in the second circuit region P is p-type, the lowerresistor 110 b may be an n-type semiconductor pattern, the barrierimpurity region 120 b may be a p-type semiconductor pattern having alower impurity concentration than the upper resistor 125 b, and theupper resistor 125 b may be a p-type semiconductor pattern.

In still another exemplary embodiment, the upper resistor 125 b and thelower resistor 110 b may have the same conductivity type. Further, thebarrier impurity region 120 b may have a different conductivity typefrom the lower and upper resistors 110 b and 125 b. For example, whenthe semiconductor substrate 100 in the second circuit region P isp-type, the lower resistor 110 b and the upper resistor 125 b may ben-type semiconductor patterns, and the barrier impurity region 120 b maybe a p-type semiconductor pattern.

A middle interlayer insulating layer 130 may be provided on the lowerinterlayer insulating layer 115 and cover the second semiconductorpattern 125 a and the upper resistor 125 b. A contact hole 130 a may beprovided to pass through the middle interlayer insulating layer 130 inthe first circuit region C and expose the second semiconductor pattern125 a. A lower electrode 140 having a smaller width than the secondsemiconductor pattern 125 a may be provided in the contact hole 130 a.The lower electrode 140 may be a titanium nitride layer or atitanium-aluminum nitride layer. An insulating spacer 135 may beinterposed between a sidewall of the contact hole 130 and the lowerelectrode 140. Meanwhile, while not illustrated in the drawing, a metalsilicide layer may be interposed between the lower electrode 140 and thesecond semiconductor pattern 125 a.

An information storage element 145 and an upper electrode 147 may beprovided on the lower electrode 140. The information storage element 145may be a phase change material layer such as a chalcogenide layer.However, the information storage element 145 is not limited to the phasechange material layer. For example, the information storage element 145may be a binary metal oxide layer. The upper electrode 147 may be atitanium nitride layer or a titanium-aluminum nitride layer, which doesnot react with the information storage element 145.

In yet another embodiment, the lower electrode 140 may partially fillthe contact hole 130 a, and the information storage element 145 may fillthe rest of the contact hole 130 a.

An upper interlayer insulating layer 155 may be provided on the middleinterlayer insulating layer 130 and cover the information storageelement 145 and the upper electrode 147. A bit line contact plug 156 maybe provided to pass through the upper interlayer insulating layer 155 inthe first circuit region C and be electrically connected with the upperelectrode 147. A bit line 157 may be provided on the upper interlayerinsulating layer 155 in the first circuit region C and cover the bitline contact plug 156.

In the second circuit region P, a first lower resistor contact plug 160a and a second lower resistor contact plug 160 b may be provided tosequentially pass through the upper, middle and lower interlayerinsulating layers 155, 130 and 115. The first lower resistor contactplug 160 a may be electrically connected with one end of the lowerresistor 110 b, and the second lower resistor contact plug 160 b may beelectrically connected with the other end of the lower resistor 110 b.In the second circuit region P, a first upper resistor contact plug 161a and a second upper resistor contact plug 161 b may be formed tosequentially pass through the upper and middle interlayer insulatinglayers 155 and 130. The first upper resistor contact plug 161 a may beelectrically connected with one end of the upper resistor 110 a, and thesecond upper resistor contact plug 161 b may be electrically connectedwith the other end of the lower resistor 110 b.

A first lower resistor interconnection 165 a covering the first lowerresistor contact plug 160 a, a second lower resistor interconnection 165b covering the lower resistor contact plug 160 b, a first upper resistorinterconnection 166 a covering the first upper resistor contact plug 161a and a second upper resistor interconnection 166 b covering the secondupper resistor contact plug 161 b may be provided on the upperinterlayer insulating layer 155 in the second circuit region P.

The first lower resistor interconnection 165 a, the second lowerresistor interconnection 165 b, the first upper resistor interconnection166 a and the second upper resistor interconnection 166 b may be spacedapart from one another. Thus, the lower resistor 110 b and the upperresistor 125 b may be individually used as resistors.

In yet another embodiment, the second upper resistor interconnection 166b and the second lower resistor interconnection 165 b may beelectrically connected with each other. For example, as shown in FIG. 3,instead of the second upper resistor interconnection 166 b and thesecond lower resistor interconnection 165 b, a resistor connectingpattern 266 simultaneously in contact with the second upper resistorcontact plug 161 b and the second lower resistor contact plug 160 b maybe provided on the upper interlayer insulating layer 155. Thus, thelower and upper resistors 110 b and 125 b are not used as individualresistors, but are serially connected with each other, such that aresistor with desired resistance may be obtained. When the lowerresistor 110 b and the upper resistor 125 a are disposed as describedabove, an area required for forming a resistor with desired resistancemay be minimized. Accordingly, due to the reduction of the area occupiedby the resistors in the present invention, the size of a semiconductorchip can be minimized. Further, the resistor formed in a singlecrystalline semiconductor pattern as described above has a higher sheetresistance than the same-size resistor formed in a polycrystallinesilicon pattern. As a result, the present invention can provide aresistor occupying a small area and having a high resistance.

A method of fabricating a semiconductor device according to exemplaryembodiments of the present invention will now be described withreference to FIGS. 1, and 2A to 2E.

Referring to FIGS. 1 and 2A, a semiconductor substrate 100 having afirst circuit region C and a second circuit region P is prepared. Thefirst circuit region C may be a memory cell array region, and the secondcircuit region P may be a peripheral circuit region. Meanwhile, thefirst circuit region, C may be an active circuit region, and the secondcircuit region P may be a passive circuit region. The semiconductorsubstrate 100 may be a silicon substrate. Alternatively, thesemiconductor substrate 100 may include a material such as SiC, SiGe andGaAs.

A separation layer 105 s may be formed in the semiconductor substrate100 to define a first active region 105 a and a second active region 105b. The first active region 105 a may be defined in the first circuitregion C, and the second active region 105 b may be defined in thesecond circuit region P. The separation layer 105 s may be formed by ashallow trench isolation technique.

Impurity ions having a different conductivity from the semiconductorsubstrate 100 in the first circuit region C may be injected into thefirst active region 105 a, thereby forming a word line 110 a having adifferent conductivity type from of the semiconductor substrate 100 inthe first circuit region C. Similarly, impurity ions having a differentconductivity type from the semiconductor substrate 100 in the secondcircuit region P may be injected into the second active region 105 a,thereby forming a lower resistor 110 b having a different conductivitytype from the semiconductor substrate 100 in the second circuit regionP. For example, when the semiconductor substrate 100 in the secondcircuit region P has a first conductivity type and the lower resistor110 b has a second conductivity type different from the firstconductivity type, the first conductivity type may be n-type, and thesecond conductivity type may be p-type. Alternatively, the firstconductivity type may be n-type, and the second conductivity type may bep-type. The lower resistor 110 b may be formed in various shapes such asbar or zigzag shapes, as seen in a plan view, to obtain desiredresistance. That is, the second active region 105 b where the lowerresistor 110 b is formed may be defined by the separation layer 105 sand formed in various shapes such as bar or zigzag shapes as seen in theplan view.

Bottom surfaces of the word line 110 a and the lower resistor 110 b maybe positioned at a higher level than that of the separation layer 105 s.Sidewalls of the word line 110 a and the lower resistor 110 b may besurrounded by the separation layer 105 s.

Meanwhile, impurity ions having a different conductivity type from ofthe semiconductor substrate 100 in the first circuit region C may beinjected into a predetermined region of the semiconductor substrate 100in the first circuit region C, thereby forming the word line 110 a.Similarly, impurity ions having a different conductivity type from thesemiconductor substrate 100 in the second circuit region P may beinjected into a predetermined region in the semiconductor substrate 100in the second circuit region P, thereby forming the lower resistor 110a, and the separation layer 105 s may be formed by a shallow trenchisolation technique.

The word line 110 a, the lower resistor 110 b and the separation layer105 s may be formed by various methods, not limited to theabove-described method. For example, the word line 110 a and the lowerresistor 110 b may be formed by an epitaxial technique. To be specific,an epitaxial semiconductor layer may be grown on the semiconductorsubstrate 100 and then patterned, such that a trench region may beformed to define a first epitaxial semiconductor pattern in the firstcircuit region C and a second epitaxial semiconductor pattern in thesecond circuit region P. Subsequently, the trench region may be filledwith an insulating layer to form the separation layer 105 s, andimpurity ions having a different conductivity type from thesemiconductor substrate 100 in the first circuit region C may beinjected into the first epitaxial semiconductor pattern to form the wordline 110 a. In addition, impurity ions having a different conductivitytype from the semiconductor substrate 100 in the second circuit region Pmay be injected into the second epitaxial semiconductor pattern to formthe lower resistor 110 b. Here, the first epitaxial semiconductorpattern may correspond to the first active region 105 a, and the secondepitaxial semiconductor pattern may correspond to the second activeregion 105 b.

Referring to FIGS. 1 and 2B, a lower interlayer insulating layer 115 maybe formed on the semiconductor substrate 100 having the word line 110 aand the lower resistor 105 b. The lower interlayer insulating layer 115may be formed of silicon oxide. The lower interlayer insulating layer115 may be patterned to form a cell diode hole 115 a exposing apredetermined region of the word line 110 a, and a peripheral resistancehole 115 b exposing a predetermined region of the lower resistor 110 b.The peripheral resistance hole 115 b may be formed in various shapessuch as a bar or zigzag shape, as seen in the plan view, to obtaindesired resistance.

A cell semiconductor patter 117 a may be formed in the cell diode hole115 a, and a peripheral semiconductor pattern 117 b may be formed in theperipheral resistance hole 115 b. The cell semiconductor pattern 117 amay be formed by a selective epitaxial growth technique by which theword line 110 a exposed through the cell diode hole 115 a is employed asa seed layer, and the peripheral semiconductor pattern 117 b may beformed by the selective epitaxial growth technique by which the lowerresistor 110 b exposed through the peripheral resistance hole 115 b isemployed as a seed layer. Thus, when the word line 110 a and the lowerresistor 110 b have a single crystalline semiconductor structure, thecell and peripheral semiconductor patterns 117 a and 117 b may also havea single crystalline semiconductor structure.

Meanwhile, forming the cell and peripheral semiconductor patterns 117 aand 117 b by the selective epitaxial growth technique may includeforming a semiconductor layer to fill the cell diode hole 115 a and theperipheral resistance hole 115 b and have a higher surface than a topsurface of the lower interlayer insulating layer 115, and planarizingthe semiconductor layer. As a result, the cell and peripheralsemiconductor patterns 117 a and 117 b may be formed to have flatsurfaces positioned at the same level as the top surface of the lowerinterlayer insulating layer 115. When the selective epitaxial growthtechnique is performed using a silicon source gas, the cell andperipheral semiconductor patterns 117 a and 117 b may be formed ofsingle crystalline silicon.

Alternatively, the cell semiconductor pattern 117 a and the peripheralsemiconductor pattern 117 b may be formed in the cell diode hole 115 aand the peripheral resistance hole 115 b, respectively, by forming anon-single crystalline semiconductor layer, i.e., an amorphous siliconlayer or a polycrystalline silicon layer using a CVD technique to fillthe cell diode hole 115 a and the peripheral resistance hole 115 b, andcrystallizing the non-single crystalline semiconductor layer using asolid phase epitaxial (SPE) technique. For example, the solid phaseepitaxial technique may include annealing the non-single crystallinesemiconductor layer at approximately 500 to 800° C. to be crystallizedinto single crystalline.

Referring to FIGS. 1 and 2C, a first semiconductor pattern 120 a may beformed by injecting impurity ions having a first conductivity type or asecond conductivity type different from the first conductivity type intoa lower region of the cell semiconductor pattern 117 a. Thus, the firstsemiconductor pattern 120 a may be formed to have the first or secondconductivity type. Further, a second semiconductor pattern 125 a may beformed by injecting impurity ions having the first conductivity typeinto an upper region of the cell semiconductor pattern 117 a.Accordingly, the second semiconductor pattern 125 a may be formed tohave the first conductivity type. Meanwhile, the ion-injection processfor forming the second semiconductor pattern 125 a may be followed bythe ion-injection process for forming the first semiconductor pattern120 a.

A barrier impurity region 120 b may be formed by injecting impurity ionshaving the first conductivity type or the second conductivity type intoa lower region of the peripheral semiconductor pattern 117 b.Accordingly, the barrier impurity region 120 b may be formed to have thefirst or second conductivity type. Further, an upper resistor 125 b maybe formed by injecting impurity ions having the first or secondconductivity type into an upper region of the peripheral semiconductorpattern 117 b. Accordingly, the upper resistor 125 b may be formed tohave the first or second conductivity type. The upper resistor 125 b maybe formed to have a top surface positioned at substantially the samelevel as that of the second semiconductor pattern 125 a. Meanwhile, theion-injection process for forming the upper resistor 125 b may befollowed by the ion-injection process for forming the barrier impurityregion 120 b. The first conductivity type may be p-type, and the secondconductivity type may be n-type. Alternatively, the first conductivitytype may be n-type, and the second conductivity type may be p-type.

Meanwhile, the first semiconductor pattern 120 a and the barrierimpurity region 120 b may be formed to have the same conductivity typeusing the same ion-injection process. Like this, the secondsemiconductor pattern 120 b and the upper resistor 125 b may be formedto have the same conductivity type using the same ion-injection process.

The first semiconductor pattern 120 a may be doped with impurities at alower concentration than the word line 110 a and the secondsemiconductor pattern 125 a, regardless of its conductivity type. Likethis, the barrier impurity region 120 b may also be doped withimpurities at a lower concentration than the lower resistor 110 b andthe upper resistor 125 b, regardless of its conductivity type.

When the first semiconductor pattern 120 a is doped with impuritieshaving the second conductivity type, the first and second semiconductorpatterns 120 a and 125 a sequentially stacked in the cell diode hole 115a constitute a cell diode D. On the other hand, when the firstsemiconductor pattern 120 a is doped with impurities having the firstconductivity type, the word line 110 a and the first semiconductorpattern 120 a in contact therewith constitute a cell diode.

Referring to FIGS. 1 and 2D, a middle interlayer insulating layer 130may be formed on the lower interlayer insulating layer 115 to cover thesecond semiconductor pattern 125 a and the upper resistor 125 b. Themiddle interlayer insulating layer 130 may be patterned, such that acontact hole 130 a exposing the second semiconductor pattern 125 a maybe formed. An insulating spacer 135 may be formed on a sidewall of thecontact hole 130 a. A lower electrode 140 filling the contact hole 130 amay be formed on the substrate having the insulating spacer 135. Thelower electrode 140 may be formed of metal which does not react with aphase change material layer to be formed in a following process. Forexample, the lower electrode 140 may be formed of a titanium nitridelayer or a titanium-aluminum nitride layer.

An information storage element 145 and an upper electrode 147 may beformed on the lower electrode 140. The information storage element 145may be formed of a phase change material layer such as a chalcogenidelayer. However, the information storage element 145 is not limited tothe phase change material layer. For example, the information storageelement 145 may be formed of a binary metal oxide layer. The upperelectrode 147 may be formed of a titanium nitride layer or atitanium-aluminum nitride layer, which do not react with the informationstorage element 145.

In yet another embodiment, the lower electrode 140 may partially fillthe contact hole 130 a. Accordingly, the information storage element 145may be formed to have a confined shape in the contact hole 130 a.

Referring to FIGS. 1 and 2E, an upper interlayer insulating layer 155may be formed on the middle interlayer insulating layer 130 to cover theinformation storage element 145 and the upper electrode 147. A bit linecontact plug 156 may be formed to pass through the upper interlayerinsulating layer 155 and to be electrically connected with the upperelectrode 147 in the first circuit region C. A bit line 157 may beformed on the upper interlayer insulating layer 155 in the first circuitregion C to cover the bit line contact plug 156.

In the second circuit region P, a first lower resistor contact plug 160a and a second lower resistor contact plug 160 b may be formed tosequentially pass through the upper, middle and lower interlayerinsulating layers 155, 130 and 115. The first lower resistor contactplug 160 a may be electrically connected with one end of the lowerresistor 110 b, and the second lower resistor contact plug 160 b may beelectrically connected with the other end of the lower resistor 110 b.In the second circuit region P, a first upper resistor contact plug 161a and a second upper resistor contact plug 161 b may be formed tosequentially pass through the upper and middle interlayer insulatinglayers 155 and 130. The first upper resistor contact plug 161 a may beelectrically connected with one end of the upper resistor 110 a, and thesecond upper resistor contact plug 161 b may be electrically connectedwith the other end of the lower resistor 110 b. Meanwhile, the first andsecond lower resistor contact plugs 160 a and 160 b, and the first andsecond upper resistor contact plugs 161 a and 161 b may be formed by thesame semiconductor process.

A first lower resistor interconnection 165 a covering the first lowerresistor contact plug 160 a, a second lower resistor interconnection 165b covering the second lower resistor contact plug 160 b, a first upperresistor interconnection 166 a covering the first upper resistor contactplug 161 a and a second upper resistor interconnection 166 b coveringthe second upper resistor contact plug 161 b may be formed on the upperinterlayer insulating layer 155 in the second circuit region P. The bitline 157, the first lower resistor interconnection 165 a, the secondlower resistor interconnection 165 b, the first upper resistorinterconnection 166 a and the second upper resistor interconnection 166b may be formed by the same semiconductor process. The first lowerresistor interconnection 165 a, the second lower resistorinterconnection 165 b, the first upper resistor interconnection 166 aand the second upper resistor interconnection 166 b may be spaced apartfrom one another. Thus, the lower resistor 110 b and the upper resistor125 b may be individually used as resistors.

In the meantime, instead of the second upper resistor interconnection166 b and the second lower resistor interconnection 165 b in FIG. 2D, aresistor connecting pattern 266 may be formed to be simultaneously incontact with the second upper resistor contact plug 161 b and the secondlower resistor contact plug 160 b, such that the lower resistor 110 band the upper resistor 125 b may be serially connected. Thus, a resistorwith desired resistance may be obtained by serially connecting the lowerresistor 110 b with the upper resistor 125 b, without using them asindividual resistors.

As described above, a separate photolithography process for forming aresistor required for a semiconductor device may be omitted by forming adiode in the first circuit region C, and forming the lower resistor 110b and/or the upper resistor 125 b in the second circuit region P. Thus,productivity of the semiconductor device can be improved. Further, thelower resistor 110 b and the upper resistor 125 b may be sequentiallystacked, and thus an area occupied by the resistor in the semiconductordevice may be minimized. In addition, since the lower resistor 110 band/or the upper resistor 125 b may be formed of a single crystallinesemiconductor material, such that a resistor may be embodied to have ahigher sheet resistance than a same-size resistor having apolycrystalline structure.

According to exemplary embodiments of the present invention, a diode anda resistor may be formed. The resistor can be formed by aphotolithography process of forming the diode, and thus a separatephotolithography process of forming the resistor may be omitted.Further, the resistor may be formed of a single crystallinesemiconductor material. Such a resistor has a higher sheet resistancethan the same-size resistor formed of a polycrystalline semiconductormaterial. Thereby, an area occupied by the resistor can be minimized.Further, a lower resistor and an upper resistor which are sequentiallystacked may be provided. Therefore, the lower resistor and the upperresistor may be individually used, or serially connected with eachother, and thus desired resistance can be easily obtained.

Although the present invention has been described with reference tocertain exemplary embodiments thereof, it will be understood by thoseskilled in the art that a variety of modifications and variations may bemade to the present invention without departing from the spirit or scopeof the present invention defined in the appended claims, and theirequivalents.

1. A semiconductor device, comprising: a semiconductor substrate havinga first circuit region and a second circuit region; a lower interlayerinsulating layer over the semiconductor substrate; a first hole passingthrough the lower interlayer insulating layer in the first circuitregion, and a second hole passing through the lower interlayerinsulating layer in the second circuit region; a first semiconductorpattern and a second semiconductor pattern sequentially stacked in thefirst hole; and a first resistor in the second hole and having a samecrystalline structure as the second semiconductor pattern.
 2. Thesemiconductor device according to claim 1, wherein the first and secondsemiconductor patterns are single crystalline semiconductor patterns. 3.The semiconductor device according to claim 1, wherein the firstresistor has a top surface positioned at a same level as that of thesecond semiconductor pattern.
 4. The semiconductor device according toclaim 1, further comprising: a word line disposed between the lowerinterlayer insulating layer and the semiconductor substrate in the firstcircuit region, and having a different conductivity type from thesemiconductor substrate in the first circuit region; and a separationlayer covering a sidewall of the word line, wherein the first holeexposes a predetermined region of the word line.
 5. The semiconductordevice according to claim 4, wherein the first semiconductor pattern hasa same conductivity type as the word line and a lower impurityconcentration than the word line, and the second semiconductor patternhas a different conductivity type from the word line.
 6. Thesemiconductor device according to claim 4, wherein the firstsemiconductor pattern has a same conductivity type as the secondsemiconductor pattern, a lower impurity concentration than the secondsemiconductor pattern, and a different conductivity type from the wordline.
 7. The semiconductor device according to claim 1, furthercomprising: a second resistor disposed between the lower interlayerinsulating layer and the semiconductor substrate in the second circuitregion, and having a different conductivity type from the semiconductorsubstrate in the second circuit region; and a separation layer coveringa sidewall of the second resistor, wherein the second hole exposes apredetermined region of the second resistor.
 8. The semiconductor deviceaccording to claim 7, further comprising: a barrier impurity regioninterposed between the first resistor and the second resistor.
 9. Thesemiconductor device according to claim 8, wherein the first and secondresistors have different conductivity types from each other, and thebarrier impurity region has a same conductivity type as the firstresistor and a lower impurity concentration than the first resistor. 10.The semiconductor device according to claim 8, wherein the first andsecond resistors have different conductivity types from each other, andthe barrier impurity region has a same conductivity type as the secondresistor and a lower impurity concentration than the second resistor.11. The semiconductor device according to claim 8, wherein the first andsecond resistors have a same conductivity type, and the barrier impurityregion has a different conductivity type from the first and secondresistors.
 12. The semiconductor device according to claim 7, furthercomprising: an upper interlayer insulating layer disposed over the lowerinterlayer insulating layer; a first lower resistor contact plugelectrically connected with one end of the second resistor and a secondlower resistor contact plug electrically connected with an other end ofthe second resistor, which pass through the upper interlayer insulatinglayer and the lower interlayer insulating layer in the second circuitregion; a first upper resistor contact plug electrically connected withthe one end of the second resistor and a second upper resistor contactplug electrically connected with the other end of the second resistor,which pass through the upper interlayer insulating layer in the secondcircuit region; a first lower resistor interconnection covering thefirst lower resistor contact plug and a second lower resistorinterconnection covering the second lower resistor contact plug, whichare provided on the upper interlayer insulating layer in the secondcircuit region; and a first upper resistor interconnection covering thefirst upper resistor contact plug and a second upper resistorinterconnection covering the second upper resistor contact plug, whichare provided on the upper interlayer insulating layer in the secondcircuit region.
 13. The semiconductor device according to claim 7,further comprising: an upper interlayer insulating layer disposed overthe lower interlayer insulating layer; a first lower resistor contactplug electrically connected with one end of the second resistor and asecond lower resistor contact plug electrically connected with an otherend of the second resistor, which pass through the upper interlayerinsulating layer and the lower interlayer insulating layer in the secondcircuit region; a first upper resistor contact plug electricallyconnected with the one end of the second resistor and a second upperresistor contact plug electrically connected with the other end of thesecond resistor, which pass through the upper interlayer insulatinglayer in the second circuit region; a first lower resistorinterconnection covering the first lower resistor contact plug and afirst upper resistor interconnection covering the first upper resistorcontact plug, which are provided on the upper interlayer insulatinglayer in the second circuit region; and a resistor connecting patternprovided on the upper interlayer insulating layer in the second circuitregion and in contact with the second lower resistor contact plug andthe second upper resistor contact plug.